Bangb-finder



P. G. NumNG. RANGE FINDER.

MPLICATIUN FILED AFR. il. ISIS.

` 2 SHEETS-suur l.

Patented Sept. 30, 1919',

INVENTOR ATTORN EV P. G. NUTTING.

RANGE FINDER.

APPucmon min APR. n. me.

Ptlltd Sept. 30, 1919.

2 SHEETS-sain 2.

4 INVENToR Pez'qyf Watg rATTORNEY PERLEY e. NUTTING, or rrr'rsiacruerr, PENNsYLvamA. E

RANGE-FINDER.

Specification of Letters Patent.

Patented Sept. 30, 1919.

Original application lled May 31| 1916, Serial No. 100,847. Divided and this application led April 11, 1918,.

Serial No.

To all whom t may concern Be it` known that I, PEnLnY G. NUTTING, of Pittsburgh, in the county of Allegheny and State of Pennsylvania, havev invented certain new and useful Improvements in Range-Finders; and I do hereby declare the following to be a full, clear, and exact description of the same. reference being had to the accompanying drawings,`form ing a part of this specification, and to the reference-numerals marked thereon.

My present invention relates to range finders or telemeters for determining the distance of an observed object from the point of observation, and it relates more Specifically to that class in which an adjustable member is employed to obtain the coincidence or alinement of two normally non-coincident or unalined images of an observed object, the displacement of the adjustable member when the images are coincident indicating on a scale the range of the object. One of the objects of my invention is to construct such' an instrument in which the visibility of the images is increased when required and theV certainty and ease of adjustment of the device thereby promoted. To these and other ends the invention resides in certain improvements and combinations of parts all as will be hereinafter more fully described, the. novel features being pointed out in the claims at the end of the specification.

In the drawings:

Figure 1 is a side elevation of a range finder constructed in accordance with` and illustratingv one embodiment of my invention;

2 is a longitudinal sectional view thereof;

Fig. 3 is a cross line 3,-31. of Fig. 2;i

Fig. 4 is a similar view on the line 4 4 of F1g.,2;p. V

Fig. 5 is a fragmentary longitudinal de tailse'cti'onal view bathe line 5,-`5of Fig'. 2';

Fig. 6' isa fragmentary detail view of-'the under side of the tube showing the scale for indicating the distance of an object;

Fig. 7; is a diagrammatic view showing the optical system of Figs, 1 and 2;

' F15., t! is a view sbowmgthe images or an sectional view on V the object out of alinement as they appear to the observer before adjustment of the in- 56 strument, and

Fig. 9 is a similar view with the imagesV coincident after adjustment.

Similar reference numerals throughout the several figures indicate the same parts. 60

This application is a division of my copnding application Serial No. 100,847, iledl ay 31, 1916 and this disclosure will involve an explanation of the range finder described therein though features of the present invention are not necessarily limited in their application to the claimed invention of said parent, case.

In carrying out my invention inthe present instance, Iy establishl a base line on the distance of separation of twosubstantially, parallel mirrors upon which separate irnages of the objects are viewed simultaneously from` an angle of. 415. One of the mirrors is semi-transparent so that the 7 5 other mirror can reflect the rays of itsl image through it and make ossible the superpositioning of the images rom a common viewpoint. As the angle ofrincidcnoe of rays from the object is diferent 0n the 80 the distance or range of the object rom the instrument. A further aid in obtalning this registration is contributed bythe use of color screens which produce images of different colors, the lack o f registration *ofy which becomes more evident through the color fringing effects that are produced.

Referring more particularly to the draw ings, and to Figs.2 and `7 thereof,`1 and 2 indicate a pair of reiectors spaced from each otherA within, a tube 3 and arranged. in 100 parallelism, to each OtlflerV at an angie of approximately 45 to the axis. oflthetube. O enings 4 are provided` in one side of the tubev adjacent the reflectors in order to ad;

mit relatively angular rays of light A B ma ne object .te the respectiva rellenas.

in the exact, reglster of the 85 Assuming that the rays A are the more d i rect rays from the image, that is, that their ath is normal to thc axis of the tube 3, it ibllows that these ra `s will be directed by the refiector 1 down tie axis of the tube and along thc axis of a telescope 5 which forms an extension of thc tube and magnifics the size of the image reduced by the reficctor from the point of o servation C which is the eye-piece of thc telescope.

The rays A being normal to the axis of the tube, it follows that the rays B emanating from the same object will strike the reflector 2 at a different angle and will be reflected through the tube at a corresponding divergence from the line of the axis thereof and of the rays A after reflection, the angle and divergence being greater with a near object than with a far object.

It being required that the images cast by both reflectors be Viewable from the same point of observation, I provide a simple arrangement for permitting the transmission of the rays B to the eye-piece C and it consists in making the reflector l semi-trans parent by incompletely silvering the back of a glass mirror plate so that 1t will both transmit and reflect the rays of light. The image formed by the rays B reiiected at 2 passes through the mirror l and becomes visible at C ltogether with the image formed by the rays A reflected at 1.

Because of the an ular direction of the rays B and theirdeflgection within the tube 3 after reflection at 2 as heretofore described, the two images as viewed at C will appear out of re ister and a double outline of the o'bject wi be seen with part of one image overlapping the other. The lack of register will be more pronounced if the object is near than if far away, accordingly as the relative an le of the ray B is greater or less. But in eit er instance, registration of the two images can be effected by bending the ray or rays B back into alinement with the axis of the, tube 3 and with the reflected ray A before the ray B reaches the semi-transparentm-irror 1. `lhi'rther, by utilizing an adjustable element `for this purpose and indicating itsmovernent upon a distance scale, a direct reading can be obtained of the distance from the instrument of a given object accordingly as therelative angle of rays A and-B' emanating therefrom require a eater or less movement of 'the adjustable e ement to straightehbne" ray into alinement with the other after reflection within the instrunient.

y I reduce coincidence of the images by the emp oyment offa deflecting member E which is inte. osed inthe path of the ray B and is mpvraiirle laterally of the axis of the tube to bend. said ray until iit coincides in direction with the reflected 'ray A. The displacement of the member E then indicates the distance of the object on a scale D. In thc present instance, the defiecting member E is one of a pair of respectively convex and concave lenses EfF of the same focal length, that Work in conjunction with each other and which normally occupy a position with their optical axes in alinement with that of the telescope. The focal lengths of these lenses are coordinated with the distance of separation of the mirrors 1 and 2 and the operation of the pair of com ensating lenses is merely that of a wedge ofpvariable angle. The deviation produced by this pair of lenses is dependent upon two factors: (l) the displacement from the coaxial position, and (2) the equivalent focal length of each component. Hence, the focal length of either lens determines and is proportional to the sensibility of the instrument, namely, the displacement required to bring into coincidence two beams of light from a given distant object.

Referring to Fig. 7, assume that the in strument has been sighted on an object at the distance R and that the images register when the lens E has been disp-laced a distance c from the o tical axis. Then since the ray B after reflection from the mirror 2 has a direction toward the focus of the lens F, the following relation holds true:

5F71? or c=%' where f is the focal length of the lens F and m is the distance between the mirrors 1 and 2.

In practice, f is so chosen that c is a distance conveniently measured on a screw (about 1 millimeter), for the range R at which the instrument is intended to operate. For example, if the mirror distance m=20 centimeters and the focal length ofthe clelecting lenses f=40 meters, the displacement o necessary for settin on an object at 10,000 meters w1ll be .8 mi limeter.

The lens E is carried in a slide 6 movable transversely of the axis of the telescope in guideways formed in blocks 7 secured in :juxtaposition by plates 8, fastened at opposite ends of the blocks 'by screws 9, the blocks being provided with cylindrical reduced portions upon which fit the two opposite portions of the tube `3. The lens F is carried lby one of the blocks 7, adjacentthe lens E. The slide 6 is moved lon itudinally by means of a screw 9 journal the plates 8 and threaded within theslide. A projection 10 on the slide extendsthrough a s ot 11 in the block 7 and coperates with divisions of a scale D to indicate the distance of the object viewed, the subdivisions vbeing read from g'aduations on a cylindrical portion 12 on t e screw coperating with an index 12, on the block 7. Springs 13 intel;- posed between one of the plates E; and, the

ed in one of slide 6 serve to prevent lost motion of the latter.

In the practice of my present invention, in order to enable the images to be seen more distinctly, I provide means for coloring them diiferently preferably b covering the openings 4 of the tube 3, with differently colored screens. For example, with a blue screen 14 anda yellow screen 15 the res ective images 16 and 17 formed by the mlrrors 1 and 2 will show blue and yellow except where they overlap, where they will show black., as shown in F1 9 and 10 in which the obJect is a cross. herefore, colored fringes will show on opposite sides of the ima unless the two are in coincidence in whic case the whole will show black.

I claim as my invention:

1. A range inder adapted to produce two images of an object movable into coincidence to obtain a distance reading and provided with means for differently coloring the two images.

2. The combination with a range Ender adapted to produce two ima ofan object movable into coincidence to o tain a distance reading, of color Iilters of diiferent hues arranged to intercept the rays of the respective images as they enter the instrument.

3. In a range finder, the combination with a pair of reflectors for directing rays of light from an object into position to enable an observer to see two separate images of the object, of means for colorin the images differently and means for delectlng the rays of one image to cause coincidence of the images. A

PERLEY G. NUTTING.

Witnesses:

Gmo. V. MILLIGAN, Sansa PAUL.

Copies el this that may be obtained for ive sente elch, by addressing the commissioner et Patenti, Washington, n. 0. 

